Dutasteride in Treating Patients With Recurrent Prostate Cancer That Did Not Respond to Androgen-Deprivation Therapy

DISEASE CHARACTERISTICS:

* Diagnosis of prostate cancer

  * Asymptomatic progressive disease despite androgen-deprivation therapy

    * Progression must occur during androgen-deprivation therapy comprising orchiectomy or luteinizing hormone-releasing hormone (LHRH) analogue with or without antiandrogen AND after antiandrogen withdrawal

      * Concurrent LHRH monotherapy (i.e., LHRH analogs, such as leuprolide acetate or goserelin) required in patients who did not undergo prior bilateral orchiectomy to assure testicular androgen suppression
* Recurrent disease, as indicated by at least 1 of the following:

  * Prostate-specific antigen (PSA) at baseline ≥ 2.0 ng/mL
  * Biopsy-confirmed local recurrence
  * Increase in size of measurable lesions on radiographic study
  * New lesion on a nuclear bone scan
  * Two successive increases in serum PSA measured at least 1 week apart

PATIENT CHARACTERISTICS:

* ECOG performance status 0-2
* Life expectancy ≥ 12 weeks
* Platelet count ≥ 100,000/mm\^3
* Hemoglobin ≥ 9.0 g/dL
* Bilirubin ≤ 2.0 mg/dL
* SGOT ≤ 4 times upper limit of normal
* Creatinine ≤ 2.0 mg/dL
* Fertile patients must use effective contraception during and for 3 months after completion of study therapy

PRIOR CONCURRENT THERAPY:

* See Disease Characteristics
* At least 28 days since prior radiotherapy and recovered
* At least 28 days since prior flutamide OR at least 42 days since prior bicalutamide or nilutamide

  * Patients who have previously progressed despite antiandrogen withdrawal and who have started antiandrogens without reduction of serum PSA are eligible without requiring a 28- or 42-day washout interval after antiandrogen withdrawal
* No other prior systemic therapies, except androgen-deprivation therapy (i.e., orchiectomy or LHRH analogues only) or antiandrogens

  * Surgery, brachytherapy, external-beam radiotherapy, and cryotherapy are not considered systemic therapies
* No other concurrent anticancer therapy
* No concurrent use of any of the following:

  * Finasteride
  * Other investigational 5α-reductase inhibitors
  * Anabolic steroids
  * Alpha-receptor blockers (e.g., indoramin, tamsulosin hydrochloride, prazosin, terazosin, alfuzosin hydrochloride, and doxazosin)
  * Drugs with antiandrogenic properties (e.g., spironolactone, flutamide, bicalutamide, cimetidine, ketoconazole, metronidazole, and progestational agents)
  * Products containing selenium ≥ 75 mcg or vitamin E ≥ 100 IU
  * Saw palmetto
  * EG6761
* No concurrent radiotherapy, including palliative radiotherapy for pain control